From patchwork Tue Feb 21 11:56:26 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Hajnoczi X-Patchwork-Id: 9584393 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 740A8600CA for ; Tue, 21 Feb 2017 12:24:59 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 6254D28066 for ; Tue, 21 Feb 2017 12:24:59 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 5381728448; Tue, 21 Feb 2017 12:24:59 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 503B928066 for ; Tue, 21 Feb 2017 12:24:57 +0000 (UTC) Received: from localhost ([::1]:44059 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cg9V2-0006SI-Am for patchwork-qemu-devel@patchwork.kernel.org; Tue, 21 Feb 2017 07:24:56 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:38602) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cg942-0006PF-HV for qemu-devel@nongnu.org; Tue, 21 Feb 2017 06:57:03 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cg940-0005Q8-Ra for qemu-devel@nongnu.org; Tue, 21 Feb 2017 06:57:02 -0500 Received: from mx1.redhat.com ([209.132.183.28]:47364) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1cg940-0005Pr-JS for qemu-devel@nongnu.org; Tue, 21 Feb 2017 06:57:00 -0500 Received: from int-mx13.intmail.prod.int.phx2.redhat.com (int-mx13.intmail.prod.int.phx2.redhat.com [10.5.11.26]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id A78C64DAF7; Tue, 21 Feb 2017 11:57:00 +0000 (UTC) Received: from localhost (ovpn-117-191.ams2.redhat.com [10.36.117.191]) by int-mx13.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id v1LBuxfO019260; Tue, 21 Feb 2017 06:56:59 -0500 From: Stefan Hajnoczi To: Date: Tue, 21 Feb 2017 11:56:26 +0000 Message-Id: <20170221115644.28264-7-stefanha@redhat.com> In-Reply-To: <20170221115644.28264-1-stefanha@redhat.com> References: <20170221115644.28264-1-stefanha@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.26 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.29]); Tue, 21 Feb 2017 11:57:00 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PULL v2 06/24] io: make qio_channel_yield aware of AioContexts X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Peter Maydell , Stefan Hajnoczi , Paolo Bonzini Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" X-Virus-Scanned: ClamAV using ClamSMTP From: Paolo Bonzini Support separate coroutines for reading and writing, and place the read/write handlers on the AioContext that the QIOChannel is registered with. Reviewed-by: Daniel P. Berrange Reviewed-by: Stefan Hajnoczi Signed-off-by: Paolo Bonzini Reviewed-by: Fam Zheng Message-id: 20170213135235.12274-7-pbonzini@redhat.com Signed-off-by: Stefan Hajnoczi --- include/io/channel.h | 47 ++++++++++++++++++++++++++-- io/channel.c | 86 +++++++++++++++++++++++++++++++++++++++------------- 2 files changed, 109 insertions(+), 24 deletions(-) diff --git a/include/io/channel.h b/include/io/channel.h index 0bc7c3f..5d48906 100644 --- a/include/io/channel.h +++ b/include/io/channel.h @@ -23,6 +23,7 @@ #include "qemu-common.h" #include "qom/object.h" +#include "qemu/coroutine.h" #include "block/aio.h" #define TYPE_QIO_CHANNEL "qio-channel" @@ -81,6 +82,9 @@ struct QIOChannel { Object parent; unsigned int features; /* bitmask of QIOChannelFeatures */ char *name; + AioContext *ctx; + Coroutine *read_coroutine; + Coroutine *write_coroutine; #ifdef _WIN32 HANDLE event; /* For use with GSource on Win32 */ #endif @@ -503,13 +507,50 @@ guint qio_channel_add_watch(QIOChannel *ioc, /** + * qio_channel_attach_aio_context: + * @ioc: the channel object + * @ctx: the #AioContext to set the handlers on + * + * Request that qio_channel_yield() sets I/O handlers on + * the given #AioContext. If @ctx is %NULL, qio_channel_yield() + * uses QEMU's main thread event loop. + * + * You can move a #QIOChannel from one #AioContext to another even if + * I/O handlers are set for a coroutine. However, #QIOChannel provides + * no synchronization between the calls to qio_channel_yield() and + * qio_channel_attach_aio_context(). + * + * Therefore you should first call qio_channel_detach_aio_context() + * to ensure that the coroutine is not entered concurrently. Then, + * while the coroutine has yielded, call qio_channel_attach_aio_context(), + * and then aio_co_schedule() to place the coroutine on the new + * #AioContext. The calls to qio_channel_detach_aio_context() + * and qio_channel_attach_aio_context() should be protected with + * aio_context_acquire() and aio_context_release(). + */ +void qio_channel_attach_aio_context(QIOChannel *ioc, + AioContext *ctx); + +/** + * qio_channel_detach_aio_context: + * @ioc: the channel object + * + * Disable any I/O handlers set by qio_channel_yield(). With the + * help of aio_co_schedule(), this allows moving a coroutine that was + * paused by qio_channel_yield() to another context. + */ +void qio_channel_detach_aio_context(QIOChannel *ioc); + +/** * qio_channel_yield: * @ioc: the channel object * @condition: the I/O condition to wait for * - * Yields execution from the current coroutine until - * the condition indicated by @condition becomes - * available. + * Yields execution from the current coroutine until the condition + * indicated by @condition becomes available. @condition must + * be either %G_IO_IN or %G_IO_OUT; it cannot contain both. In + * addition, no two coroutine can be waiting on the same condition + * and channel at the same time. * * This must only be called from coroutine context */ diff --git a/io/channel.c b/io/channel.c index ce470d7..cdf7454 100644 --- a/io/channel.c +++ b/io/channel.c @@ -21,7 +21,7 @@ #include "qemu/osdep.h" #include "io/channel.h" #include "qapi/error.h" -#include "qemu/coroutine.h" +#include "qemu/main-loop.h" bool qio_channel_has_feature(QIOChannel *ioc, QIOChannelFeature feature) @@ -238,36 +238,80 @@ off_t qio_channel_io_seek(QIOChannel *ioc, } -typedef struct QIOChannelYieldData QIOChannelYieldData; -struct QIOChannelYieldData { - QIOChannel *ioc; - Coroutine *co; -}; +static void qio_channel_set_aio_fd_handlers(QIOChannel *ioc); +static void qio_channel_restart_read(void *opaque) +{ + QIOChannel *ioc = opaque; + Coroutine *co = ioc->read_coroutine; + + ioc->read_coroutine = NULL; + qio_channel_set_aio_fd_handlers(ioc); + aio_co_wake(co); +} -static gboolean qio_channel_yield_enter(QIOChannel *ioc, - GIOCondition condition, - gpointer opaque) +static void qio_channel_restart_write(void *opaque) { - QIOChannelYieldData *data = opaque; - qemu_coroutine_enter(data->co); - return FALSE; + QIOChannel *ioc = opaque; + Coroutine *co = ioc->write_coroutine; + + ioc->write_coroutine = NULL; + qio_channel_set_aio_fd_handlers(ioc); + aio_co_wake(co); } +static void qio_channel_set_aio_fd_handlers(QIOChannel *ioc) +{ + IOHandler *rd_handler = NULL, *wr_handler = NULL; + AioContext *ctx; + + if (ioc->read_coroutine) { + rd_handler = qio_channel_restart_read; + } + if (ioc->write_coroutine) { + wr_handler = qio_channel_restart_write; + } + + ctx = ioc->ctx ? ioc->ctx : iohandler_get_aio_context(); + qio_channel_set_aio_fd_handler(ioc, ctx, rd_handler, wr_handler, ioc); +} + +void qio_channel_attach_aio_context(QIOChannel *ioc, + AioContext *ctx) +{ + AioContext *old_ctx; + if (ioc->ctx == ctx) { + return; + } + + old_ctx = ioc->ctx ? ioc->ctx : iohandler_get_aio_context(); + qio_channel_set_aio_fd_handler(ioc, old_ctx, NULL, NULL, NULL); + ioc->ctx = ctx; + qio_channel_set_aio_fd_handlers(ioc); +} + +void qio_channel_detach_aio_context(QIOChannel *ioc) +{ + ioc->read_coroutine = NULL; + ioc->write_coroutine = NULL; + qio_channel_set_aio_fd_handlers(ioc); + ioc->ctx = NULL; +} void coroutine_fn qio_channel_yield(QIOChannel *ioc, GIOCondition condition) { - QIOChannelYieldData data; - assert(qemu_in_coroutine()); - data.ioc = ioc; - data.co = qemu_coroutine_self(); - qio_channel_add_watch(ioc, - condition, - qio_channel_yield_enter, - &data, - NULL); + if (condition == G_IO_IN) { + assert(!ioc->read_coroutine); + ioc->read_coroutine = qemu_coroutine_self(); + } else if (condition == G_IO_OUT) { + assert(!ioc->write_coroutine); + ioc->write_coroutine = qemu_coroutine_self(); + } else { + abort(); + } + qio_channel_set_aio_fd_handlers(ioc); qemu_coroutine_yield(); }